A demolition hammer is frequently used at a work site to break apart things such as rock, concrete, asphalt, frozen ground, or other materials. The demolition hammer may be mounted to a machine, such as, a backhoe or an excavator, for example. Such hammers may include a pneumatically or hydraulically actuated power cell having an impact system operatively coupled to a tool that extends from the hammer to engage the object to be broken apart.
The power cell of a demolition hammer may be positioned within a housing and supported on buffers, which allow some relative movement between the power cell and the housing. A plurality of wear plates may be interposed between the power cell and the interior of the housing. For example, a hammer with a square housing may have four separate wear plates (front, back, right side, and left side) that surround a portion of the power cell.
In operation, a demolition hammers can be exposed to a lot of dust, dirt and other contaminants which tend to be abrasive. This abrasive material can infiltrate a gap between the tool and the lower bushing and enter the housing. The abrasive material that becomes stuck between the front head and the wear plates can cause wear of the front head of the hammer. The front head wear caused by this trapped debris can reduce the useful life of the demolition hammer and/or prevent the front head from being used for rebuilding the hammer. Furthermore, the movement of the power cell relative to the housing during operation can result in wear of the wear plates. Thus, the wear plates may need periodic replacement.
U.S. Pat. No. 8,061,450 is entitled, “Percussion Drilling Assembly Having Erosion Retarding Casing,” and is directed to a percussion drilling assembly for drilling through earthen formations and forming a borehole. In some embodiments, the drilling assembly includes a retainer sleeve having an upper end with an outer diameter and a tubular casing engaging the retainer sleeve. The tubular casing includes a first, second, and third tubular portion. The first tubular portion engages the upper end of the retainer sleeve at a first end having an outer diameter substantially equal to the outer diameter of the retainer sleeve. The second tubular portion is connected to the first tubular portion at a first end and has a second end with an outer diameter that differs from the outer diameter of the retainer sleeve. The third tubular portion is coupled to the second tubular portion. The first and third tubular portions each have a length configured to enable gripping of the tubular casing using tongs.
There is a continued need in the art to provide additional solutions for the reduction of the wear of the components of a demolition hammer as a result of the abrasive environment within which it is frequently operated. For example, there is a continued need for a demolition hammer solution to help reduce the wear of the front head caused by abrasive debris trapped between the wear plate and the front head.
It will be appreciated that this background description has been created by the inventors to aid the reader, and is not to be taken as an indication that any of the indicated problems were themselves appreciated in the art. While the described principles can, in some respects and embodiments, alleviate the problems inherent in other systems, it will be appreciated that the scope of the protected innovation is defined by the attached claims, and not by the ability of any disclosed feature to solve any specific problem noted herein.